; *****************************************************************************************
; Copyright © [01/26/1999] Scenix Semiconductor, Inc. All rights reserved.
;
; Scenix Semiconductor, Inc. assumes no responsibility or liability for
; the use of this [product, application, software, any of these products].
; Scenix Semiconductor conveys no license, implicitly or otherwise, under
; any intellectual property rights.
; Information contained in this publication regarding (e.g.: application,
; implementation) and the like is intended through suggestion only and may
; be superseded by updates. Scenix Semiconductor makes no representation
; or warranties with respect to the accuracy or use of these information,
; or infringement of patents arising from such use or otherwise.
;*****************************************************************************************
; Filename: bell202_modem_at.src
;
; Author: Chris Fogelklou
; Applications Engineer
; Scenix Semiconductor Inc.
;
; Revision: 3.63
;
; Date: January 26, 1999.
;
; Part: SX28AC rev. 2.5
;
; Freq: 50Mhz
;
; Compiled using Parallax SX-Key software v1.0
;
; Program Description:
; This program is a full implementation of a half-duplex bell202 modem
; which transmits and receives at 1200bps. The baud rate of the uart
; connected to it should be set to 1200,N,8,1.
; The necessary baud rate can be changed easily in this software by
; using the defines present in the sx_demo software, which is available
; on the web. On power-up, this software generates a prompt with some
; instructions on usage. This version of of the software has these
; functions implemented...
; - DTMF output for dialing
; - FSK output
; - FSK input
; - 1200 baud UART for communication with a PC or terminal
; - Small AT command set
; - Ring detection
; - Buffer for AT command storage
; - String parser for AT command processing. Allows easy addition of
; - AT commands.
;
; Authors: Chris Fogelklou, Scenix Semiconductor Inc.
; Written: 98/12/18 to 98/12/21
; Version: 3.63
; Last revised: 11/29/99
; Revisions: 3.0 began with the tx_modem_1_0.src software and combined it
; with the fsk_rx_1_0 software.
; 3.1 modified so that UART speed = Transmit speed and this
; is settable by changing the divider_bit
; 3.2 has much better documentation inside the software, and
; it also includes a transmit-only mode for error-free file
; transmission at 1200 baud and a receive-only mode for
; error-free file reception at 1200 baud. Future revisions
; will fix the 1200-baud file transfer errors. Debugging work
; is involved.
; 3.4 fixes the bug in the DTMF generation code, which was
; causing the output signal to clip and it also adds "twist"
; to the DTMF generation code, which is required. The high
; frequency signal should be 1.25 times greater in amplitude
; than the low frequency signal. (1/5/99)
; 3.5 Fixes the bug in the UART code which is causing
; the modem to miss characters during file transfer.
; (UART process)
; 3.51 Fixes a bug caused by the bug fix in 3.5, in which the
; pwm DC value is not reset to 2.5V when the output is disabled
; 3.53 Modified format for new Scenix template, and to compile for
; SX28 or SX48/52 target devices.
;
;
; I/O USAGE: INPUTS:
;
; rx_pin equ ra.1 ; RS-232 input pin
; fsk_in equ rb.1 ; FSK input pin
;
; OUTPUTS:
;
; PWM_pin equ ra.0 ; PWM output for D/A
; tx_pin equ ra.2 ; RS-232 output pin
; in_out equ ra.3 ; Enables/Disables output
; ; on SX DTMF DEMO boards.
; led_pin equ rb.0 ; LED output pin
; fsk input pin is rb.1 ; does not need a define, uses a bitmask
; hook equ rb.4 ; Selects on-hook/off-hook
;
; RESOURCES:
; Program Memory: TBD
; Data Memory: TBD
;*****************************************************************************************
;*****************************************************************************************
; Target SX
; Uncomment one of the following lines to choose the SX18AC, SX20AC, SX28AC, SX48BD/ES,
; SX48BD, SX52BD/ES or SX52BD. For SX48BD/ES and SX52BD/ES, uncomment both defines,
; SX48_52 and SX48_52_ES.
;*****************************************************************************************
;SX18_20
;SX28
SX48_52
;SX48_52_ES
;*****************************************************************************************
; Assembler Used
; Uncomment the following line if using the Parallax SX-Key assembler. SASM assembler
; enabled by default.
;*****************************************************************************************
;SX_Key
;*********************************************************************************
; Assembler directives:
; high speed external osc, turbo mode, 8-level stack, and extended option reg.
;
; SX18/20/28 - 4 pages of program memory and 8 banks of RAM enabled by default.
; SX48/52 - 8 pages of program memory and 16 banks of RAM enabled by default.
;
;*********************************************************************************
IFDEF SX_Key ;SX-Key Directives
IFDEF SX18_20 ;SX18AC or SX20AC device directives for SX-Key
device SX18L,oscxt4,turbo,stackx_optionx
ENDIF
IFDEF SX28 ;SX28AC device directives for SX-Key
device SX28L,oscxt4,turbo,stackx_optionx
ENDIF
IFDEF SX48_52_ES ;SX48BD/ES or SX52BD/ES device directives for SX-Key
device oschs,turbo,stackx,optionx
ELSE
IFDEF SX48_52 ;SX48/52/BD device directives for SX-Key
device oschs2
ENDIF
ENDIF
freq 50_000_000
ELSE ;SASM Directives
IFDEF SX18_20 ;SX18AC or SX20AC device directives for SASM
device SX18,oschs2,turbo,stackx,optionx
ENDIF
IFDEF SX28 ;SX28AC device directives for SASM
device SX28,oschs2,turbo,stackx,optionx
ENDIF
IFDEF SX48_52_ES ;SX48BD/ES or SX52BD/ES device directives for SASM
device SX52,oschs,turbo,stackx,optionx
ELSE
IFDEF SX48_52 ;SX48BD or SX52BD device directives for SASM
device SX52,oschs2,stackx,optionx
ENDIF
ENDIF
ENDIF
id ' ' ;
reset reset_entry ; set reset vector
IFDEF SX_Key
;*****************************************************************************************
; Watches (For Debug in SX_Key software V.1.0 +)
;*****************************************************************************************
watch freq_acc_high,16,uhex
watch freq_count_high,16,uhex
watch freq_count_high2,16,uhex
watch byte,1,fstr
watch curr_sin,8,sdec
watch sinvel,8,sdec
watch pwm0,8,udec
watch ring_duration,8,udec
watch timer_flag,1,ubin
watch timer_l,16,uhex
watch temp,8,uhex
watch fsk_bit_delay,8,uhex
watch fsk_last_bit,1,ubin
watch fsk_rx_en,1,ubin
watch flags,8,ubin
watch ascii_buffer,16,zstr
watch ascii_buffer2,16,zstr
watch ascii_buffer3,16,zstr
watch ascii_buffer4,16,zstr
watch ascii_index,8,udec
watch fsr,8,udec
watch indf,1,fstr
watch wreg,1,fstr
watch rings,8,udec
watch plus_count,8,udec
ENDIF
;*****************************************************************************************
; Macros
;*****************************************************************************************
;*********************************************************************************
; Macro: _bank
; Sets the bank appropriately for all revisions of SX.
;
; This is required since the bank instruction has only a 3-bit operand, it cannot
; be used to access all 16 banks of the SX48/52. For this reason FSR.4 (for SX48/52BD/ES)
; or FSR.7 (SX48/52bd production release) needs to be set appropriately, depending
; on the bank address being accessed. This macro fixes this.
;
; So, instead of using the bank instruction to switch between banks, use _bank instead.
;
;*********************************************************************************
_bank macro 1
noexpand
bank \1
IFDEF SX48_52
IFDEF SX48_52_ES
IF \1 & %00010000 ;SX48BD/ES and SX52BD/ES (engineering sample) bank instruction
expand
setb fsr.4 ;modifies FSR bits 5,6 and 7. FSR.4 needs to be set by software.
noexpand
ENDIF
ELSE
IF \1 & %10000000 ;SX48BD and SX52BD (production release) bank instruction
expand
setb fsr.7 ;modifies FSR bits 4,5 and 6. FSR.7 needs to be set by software.
noexpand
ELSE
expand
clrb fsr.7
noexpand
ENDIF
ENDIF
ENDIF
endm
;*********************************************************************************
; Macro: _mode
; Sets the MODE register appropriately for all revisions of SX.
;
; This is required since the MODE (or MOV M,#) instruction has only a 4-bit operand.
; The SX18/20/28AC use only 4 bits of the MODE register, however the SX48/52BD have
; the added ability of reading or writing some of the MODE registers, and therefore use
; 5-bits of the MODE register. The MOV M,W instruction modifies all 8-bits of the
; MODE register, so this instruction must be used on the SX48/52BD to make sure the MODE
; register is written with the correct value. This macro fixes this.
;
; So, instead of using the MODE or MOV M,# instructions to load the M register, use
; _mode instead.
;
;*********************************************************************************
_mode macro 1
noexpand
IFDEF SX48_52
expand
mov w,#\1 ;loads the M register correctly for the SX48BD and SX52BD
mov m,w
noexpand
ELSE
expand
mov m,#\1 ;loads the M register correctly for the SX18AC, SX20AC
;and SX28AC
noexpand
ENDIF
endm
;*************************************************************
; Macros
;*************************************************************
; old_board ; uncomment this if using with old boards.
; ; Boards marked REV1.4 are newer. Boards
; ; Boards with no rev number are older.
; ; If board is green and uses a DIP package,
; ; keep the oldboard macro commented.
;*********************************************************************************
; Macro: enable_o
;
; This macro enables the output
;*********************************************************************************
enable_o macro 0
ifdef old_board
clrb in_out ; switch on the new modem boards.
else
setb in_out
endif
clr flags
endm
;*****************************************************************************************
; Data Memory address definitions
; These definitions ensure the proper address is used for banks 0 - 7 for 2K SX devices
; (SX18/20/28) and 4K SX devices (SX48/52).
;*****************************************************************************************
IFDEF SX48_52
global_org = $0A
bank0_org = $00
bank1_org = $10
bank2_org = $20
bank3_org = $30
bank4_org = $40
bank5_org = $50
bank6_org = $60
bank7_org = $70
ELSE
global_org = $08
bank0_org = $10
bank1_org = $30
bank2_org = $50
bank3_org = $70
bank4_org = $90
bank5_org = $B0
bank6_org = $D0
bank7_org = $F0
ENDIF
;*****************************************************************************************
; Global Register definitions
; NOTE: Global data memory starts at $0A on SX48/52 and $08 on SX18/20/28.
;*****************************************************************************************
org global_org
flags equ global_org+0
rx_flag equ flags.0 ; Signifies a bit recieved via. RS-232
dtmf_gen_en equ flags.1 ; Signifies whether or not DTMF output is enabled
fsk_tx_en equ flags.2 ; These flags are the same and they both
fsk_transmitting equ flags.3 ; indicate when the UART is transmitting
timer_flag equ flags.4 ; Flags a rollover of the timers.
fsk_rx_en equ flags.5 ; Enables the FSK receiver.
fsk_rx_flag equ flags.6 ; Signifies reception of FSK
ring_det_en equ flags.7 ; Enables the ring detector
temp equ global_org+1 ; Temporary storage register for use by the main program
divider equ global_org+2 ; used to divide down the UART to 1200 baud
IRQ_temp equ global_org+3 ; Temporary register for use by the interrupt service routine
ascii_index equ global_org+4 ; Register used for the ascii buffering
command_index equ global_org+5 ; Register used as an index to the command to compare to.
;*****************************************************************************************
; RAM Bank Register definitions
;*****************************************************************************************
;*********************************************************************************
; Bank 0
;*********************************************************************************
org bank0_org
bank0 = $
sin_gen_bank = $
freq_acc_high ds 1 ;
freq_acc_low ds 1 ; 16-bit accumulator which decides when to increment the sine wave
freq_acc_high2 ds 1 ;
freq_acc_low2 ds 1 ; 16-bit accumulator which decides when to increment the sine wave
freq_count_high ds 1 ; freq_count = Frequency * 6.83671552
freq_count_low ds 1 ; 16-bit counter which decides which frequency for the sine wave
freq_count_high2 ds 1 ; freq_count = Frequency * 6.83671552
freq_count_low2 ds 1 ; 16-bit counter which decides which frequency for the sine wave
curr_sin ds 1 ; The current value of the imitation sin wave
sinvel ds 1 ; The velocity of the sin wave
curr_sin2 ds 1 ; The current value of the imitation sin wave
sinvel2 ds 1 ; The velocity of the sin wave
PWM_bank = $
pwm0_acc ds 1 ; PWM accumulator
pwm0 ds 1 ; current PWM output
timers = $
timer_l ds 1
timer_h ds 1
;*********************************************************************************
; Bank 1
;*********************************************************************************
org bank1_org
bank1 = $
serial = $ ;UART bank
tx_high ds 1 ;hi byte to transmit
tx_low ds 1 ;low byte to transmit
tx_count ds 1 ;number of bits sent
tx_divide ds 1 ;xmit timing (/16) counter
rx_count ds 1 ;number of bits received
rx_divide ds 1 ;receive timing counter
rx_byte ds 1 ;buffer for incoming byte
string ds 1
byte ds 1
plus_count ds 1 ;counts the number of '+'s received
;while in FSK_IO mode.
;*********************************************************************************
; Bank 2
;*********************************************************************************
org bank2_org
bank2 = $
fsk_transmit_bank = $
fsk_bit_delay ds 1
fsk_tx_byte ds 1
fsk_flags ds 1
fsk_last_bit equ fsk_flags.0
fsk_tx_counter ds 1
fsk_receive_bank = $
fsk_trans_count ds 1 ; This register counts the number of counts
; between transitions at the pin
rb_past_state ds 1 ; This register keeps track of the previous
fsk_rx_count ds 1 ; number of bits received
fsk_rx_divide ds 1 ; bit delay
fsk_rx_byte ds 1 ; buffer for incoming byte
fsk_current_in equ fsk_flags.1 ; The bit represented by the current input frequency
fsk_trans equ fsk_flags.2
;*********************************************************************************
; Bank 3
;*********************************************************************************
org bank3_org
bank3 = $
ring_detect_bank = $
ring_timer_low ds 1
ring_timer_high ds 1
ring_flags ds 1
ring_timer_flag equ ring_flags.0
ringing_1 equ ring_flags.1
ringing_2 equ ring_flags.2
long_ring equ ring_flags.3
ring_pause equ ring_flags.4
ring_captured equ ring_flags.5
ring_off_timer_1 ds 1
ring_timer ds 1
ring_duration ds 1
ring_duration_timer ds 1
answer_rings ds 1
rings ds 1
;*********************************************************************************
; Bank 4
;*********************************************************************************
org bank4_org
bank4 = $
ascii_buffer = $
;*********************************************************************************
; Bank 5
;*********************************************************************************
org bank5_org
bank5 = $
ascii_buffer2 = $
;*********************************************************************************
; Bank 6
;*********************************************************************************
org bank6_org
bank6 = $
ascii_buffer3 = $
;*********************************************************************************
; Bank 7
;*********************************************************************************
org bank7_org
bank7 = $
ascii_buffer4 = $
IFDEF SX48_52
;*********************************************************************************
; Bank 8
;*********************************************************************************
org $80 ;bank 8 address on SX52
bank8 = $
;*********************************************************************************
; Bank 9
;*********************************************************************************
org $90 ;bank 9 address on SX52
bank9 = $
;*********************************************************************************
; Bank A
;*********************************************************************************
org $A0 ;bank A address on SX52
bankA = $
;*********************************************************************************
; Bank B
;*********************************************************************************
org $B0 ;bank B address on SX52
bankB = $
;*********************************************************************************
; Bank C
;*********************************************************************************
org $C0 ;bank C address on SX52
bankC = $
;*********************************************************************************
; Bank D
;*********************************************************************************
org $D0 ;bank D address on SX52
bankD = $
;*********************************************************************************
; Bank E
;*********************************************************************************
org $E0 ;bank E address on SX52
bankE = $
;*********************************************************************************
; Bank F
;*********************************************************************************
org $F0 ;bank F address on SX52
bankF = $
ENDIF
;*****************************************************************************************
; Port Assignment
;*****************************************************************************************
RA_latch equ %00001000 ;SX18/20/28/48/52 port A latch init
RA_DDIR equ %11110010 ;SX18/20/28/48/52 port A DDIR value
RA_LVL equ %00001110 ;SX18/20/28/48/52 port A LVL value
RA_PLP equ %11111111 ;SX18/20/28/48/52 port A PLP value
RB_latch equ %11101110 ;SX18/20/28/48/52 port B latch init
RB_DDIR equ %00101110 ;SX18/20/28/48/52 port B DDIR value
RB_ST equ %11111101 ;SX18/20/28/48/52 port B ST value
RB_LVL equ %00000000 ;SX18/20/28/48/52 port B LVL value
RB_PLP equ %11111111 ;SX18/20/28/48/52 port B PLP value
RC_latch equ %00000000 ;SX18/20/28/48/52 port C latch init
RC_DDIR equ %11111010 ;SX18/20/28/48/52 port C DDIR value
RC_ST equ %11111111 ;SX18/20/28/48/52 port C ST value
RC_LVL equ %00000000 ;SX18/20/28/48/52 port C LVL value
RC_PLP equ %11111111 ;SX18/20/28/48/52 port C PLP value
IFDEF SX48_52 ;SX48BD/52BD Port initialization values
RD_latch equ %00000000 ;SX48/52 port D latch init
RD_DDIR equ %11111111 ;SX48/52 port D DDIR value
RD_ST equ %11111111 ;SX48/52 port D ST value
RD_LVL equ %00000000 ;SX48/52 port D LVL value
RD_PLP equ %11111111 ;SX48/52 port D PLP value
RE_latch equ %00000000 ;SX48/52 port E latch init
RE_DDIR equ %11111111 ;SX48/52 port E DDIR value
RE_ST equ %11111111 ;SX48/52 port E ST value
RE_LVL equ %00000000 ;SX48/52 port E LVL value
RE_PLP equ %11111111 ;SX48/52 port E PLP value
ENDIF
;*********************************************************************************
; Pin Definitions
;*********************************************************************************
PWM_pin equ ra.0 ; PWM output for D/A
rx_pin equ ra.1 ; RS-232 Input pin
tx_pin equ ra.2 ; RS-232 Output pin
in_out equ ra.3 ; Switches between output
; and input on SX DTMF DEMO boards.
led_pin equ rb.0 ; Flashes while characters are
; being received.
;fsk input pin is rb.1 ; does not need a define, uses a bitmask
ring equ rb.3 ; Ring detection pin
hook equ rb.4 ; Goes on/off-hook.
;*****************************************************************************************
; Program constants
;*****************************************************************************************
int_period equ 163 ;RTCC Interrupt rate
;*********************************************************************************
; Equates for the FSK receive part of the modem
;*********************************************************************************
glitch_th equ 10 ; The threshold which defines a glitch (small spike which should be ignored)
low_count_error_th equ 30 ; The lowest count allowed for a high frequency
low_high_th equ 95 ; The lowest count allowed for a low frequency
high_count_error_th equ 150 ; The highest count allowed for a low frequency
; *** 1200 baud using a 1/2 counter.
baud_bit = 7 ;for 1200 baud fsk
start_delay = 128+64+1 ; " " "
divider_bit = 1 ;1 for 1200 baud, 2 for 600 baud, 3 for 300 baud.
;**************************************************************************
; Equates for common data comm frequencies (DTMF generation)
;**************************************************************************
f697_h equ $012 ; DTMF Frequency
f697_l equ $09d
f770_h equ $014 ; DTMF Frequency
f770_l equ $090
f852_h equ $016 ; DTMF Frequency
f852_l equ $0c0
f941_h equ $019 ; DTMF Frequency
f941_l equ $021
f1209_h equ $020 ; DTMF Frequency
f1209_l equ $049
f1336_h equ $023 ; DTMF Frequency
f1336_l equ $0ad
f1477_h equ $027 ; DTMF Frequency
f1477_l equ $071
f1633_h equ $02b ; DTMF Frequency
f1633_l equ $09c
f1300_h equ $022 ; 1300Hz Signifies HIGH data in Bell202 Spec
f1300_l equ $0b7
f2100_h equ $038 ; 2100Hz Signifies LOW data in Bell202 Spec
f2100_l equ $015
IFDEF SX48_52
;*********************************************************************************
; SX48BD/52BD Mode addresses
; *On SX48BD/52BD, most registers addressed via mode are read and write, with the
; exception of CMP and WKPND which do an exchange with W.
;*********************************************************************************
; Timer (read) addresses
TCPL_R equ $00 ;Read Timer Capture register low byte
TCPH_R equ $01 ;Read Timer Capture register high byte
TR2CML_R equ $02 ;Read Timer R2 low byte
TR2CMH_R equ $03 ;Read Timer R2 high byte
TR1CML_R equ $04 ;Read Timer R1 low byte
TR1CMH_R equ $05 ;Read Timer R1 high byte
TCNTB_R equ $06 ;Read Timer control register B
TCNTA_R equ $07 ;Read Timer control register A
; Exchange addresses
CMP equ $08 ;Exchange Comparator enable/status register with W
WKPND equ $09 ;Exchange MIWU/RB Interrupts pending with W
; Port setup (read) addresses
WKED_R equ $0A ;Read MIWU/RB Interrupt edge setup, 0 = falling, 1 = rising
WKEN_R equ $0B ;Read MIWU/RB Interrupt edge setup, 0 = enabled, 1 = disabled
ST_R equ $0C ;Read Port Schmitt Trigger setup, 0 = enabled, 1 = disabled
LVL_R equ $0D ;Read Port Schmitt Trigger setup, 0 = enabled, 1 = disabled
PLP_R equ $0E ;Read Port Schmitt Trigger setup, 0 = enabled, 1 = disabled
DDIR_R equ $0F ;Read Port Direction
; Timer (write) addresses
CLR_TMR equ $10 ;Resets 16-bit Timer
TR2CML_W equ $12 ;Write Timer R2 low byte
TR2CMH_W equ $13 ;Write Timer R2 high byte
TR1CML_W equ $14 ;Write Timer R1 low byte
TR1CMH_W equ $15 ;Write Timer R1 high byte
TCNTB_W equ $16 ;Write Timer control register B
TCNTA_W equ $17 ;Write Timer control register A
; Port setup (write) addresses
WKED_W equ $1A ;Write MIWU/RB Interrupt edge setup, 0 = falling, 1 = rising
WKEN_W equ $1B ;Write MIWU/RB Interrupt edge setup, 0 = enabled, 1 = disabled
ST_W equ $1C ;Write Port Schmitt Trigger setup, 0 = enabled, 1 = disabled
LVL_W equ $1D ;Write Port Schmitt Trigger setup, 0 = enabled, 1 = disabled
PLP_W equ $1E ;Write Port Schmitt Trigger setup, 0 = enabled, 1 = disabled
DDIR_W equ $1F ;Write Port Direction
ELSE
;*********************************************************************************
; SX18AC/20AC/28AC Mode addresses
; *On SX18/20/28, all registers addressed via mode are write only, with the exception of
; CMP and WKPND which do an exchange with W.
;*********************************************************************************
; Exchange addresses
CMP equ $08 ;Exchange Comparator enable/status register with W
WKPND equ $09 ;Exchange MIWU/RB Interrupts pending with W
; Port setup (read) addresses
WKED_W equ $0A ;Write MIWU/RB Interrupt edge setup, 0 = falling, 1 = rising
WKEN_W equ $0B ;Write MIWU/RB Interrupt edge setup, 0 = enabled, 1 = disabled
ST_W equ $0C ;Write Port Schmitt Trigger setup, 0 = enabled, 1 = disabled
LVL_W equ $0D ;Write Port Schmitt Trigger setup, 0 = enabled, 1 = disabled
PLP_W equ $0E ;Write Port Schmitt Trigger setup, 0 = enabled, 1 = disabled
DDIR_W equ $0F ;Write Port Direction
ENDIF
;*****************************************************************************************
; Interrupt Service Routine
;*****************************************************************************************
; Note: The interrupt code must always originate at address $0.
;
; Interrupt Frequency = (Cycle Frequency / -(retiw value)) For example:
; With a retiw value of -217 and an oscillator frequency of 50MHz, this
; code runs every 4.34us.
;*****************************************************************************************
org $0
;*********************************************************************************
; Virtual Peripheral:
;
;
; Input variable(s):
; Output variable(s):
; Variable(s) affected:
; Flag(s) affected:
;*********************************************************************************
;******************************************************************************
PWM_OUTPUT
; This outputs the current value of pwm0 to the PWM_pin. This generates
; an analog voltage at PWM_pin after filtering.
; INPUTS:
; pwm0 - The value from 0-255 representing the analog voltage to be
; output by the PWM_pin
;**************************************************************************
bank PWM_bank
add pwm0_acc,pwm0 ; add the PWM output to the accumulator
snc
jmp :carry ; if there was no carry, then clear
; the PWM_pin
clrb PWM_pin
jmp PWM_out
:carry
setb PWM_pin ; otherwise set the PWM_pin
PWM_out
;**************************************************************************
TASK_SWITCHER
; Now decide which task to do... we may only do one, and the transmit
; takes priority over the receive functions.
; INPUTS:
; flags - Depending on which of the flags are set in the flags register,
; either FSK transmission, FSK reception, or DTMF generation
; will occur.
;**************************************************************************
snb ring_det_en
call @ring_detect
jnb fsk_tx_en,:fsk_tx_out ; If FSK transmit is enabled
call @sine_generator2 ; only use one of the sine generators
call @FSK_TX_UART ; perform the transmit UART first
jmp :TASK_OUT ; and then skip over DTMF because can't do
:fsk_tx_out ; both at once
jnb dtmf_gen_en,:sine_gen_out ; if dtmf generation is enabled
call @sine_generator1 ; do it.
jmp :TASK_OUT
:sine_gen_out
jnb fsk_rx_en,:fsk_rx_out ; jump out if the FSK receiver is not enabled
call @FSK_RECEIVE
jmp :TASK_OUT
:fsk_rx_out
:TASK_OUT
;**************************************************************************
:transmit
; This is an asynchronous transmitter for RS-232 transmission
; INPUTS:
; divider.divider_bit - Transmitter/receiver only executes when this bit is = 1
; tx_divide.baud_bit - Transmitter only executes when this bit is = 1
; tx_high - Part of the data to be transmitted
; tx_low - Some more of the data to be transmitted
; tx_count - Counter which counts the number of bits transmitted.
; OUTPUTS:
; tx_pin - Sets/Clears this pin to accomplish the transmission.
;**************************************************************************
jnb divider.divider_bit,:rxdone ; cut the UART speed down to 1200/600/300
; depending on divider bit
bank serial
clrb tx_divide.baud_bit ;clear xmit timing count flag
inc tx_divide ;only execute the transmit routine
STZ ;set zero flag for test
SNB tx_divide.baud_bit ; every 2^baud_bit interrupt
test tx_count ;are we sending?
JZ :receive ;if not, go to :receive
clc ;yes, ready stop bit
rr tx_high ; and shift to next bit
rr tx_low ;
dec tx_count ;decrement bit counter
movb tx_pin,/tx_low.6 ;output next bit
;**************************************************************************
:receive
; This is an asynchronous receiver for RS-232 reception
; INPUTS:
; rx_pin - Pin which RS-232 is received on.
; OUTPUTS:
; rx_byte - The byte received
; rx_flag - Set when a bRyte is received.
;**************************************************************************
movb c,rx_pin ;get current rx bit
test rx_count ;currently receiving byte?
jnz :rxbit ;if so, jump ahead
mov w,#9 ;in case start, ready 9 bits
sc ;skip ahead if not start bit
mov rx_count,w ;it is, so renew bit count
mov rx_divide,#start_delay ;ready 1.5 bit periods
:rxbit djnz rx_divide,:rxdone ;middle of next bit?
setb rx_divide.baud_bit ;yes, ready 1 bit period
dec rx_count ;last bit?
sz ;if not
rr rx_byte ; then save bit
snz ;if so
setb rx_flag ; then set flag
:rxdone
;**************************************************************************
do_timers
; The timer will tick at the interrupt rate (3.26us for 50MHz.) To set up
; the timers, move in FFFFh - (value that corresponds to the time.) Example:
; for 1ms = 1ms/3.26us = 306 dec = 132 hex so move in $FFFF - $0132 = $FECD
;**************************************************************************
bank timers ; Switch to the timer bank
mov w,#1
add timer_l,w ; add 1 to timer_l
jnc :timer_out ; if it's not zero, then
add timer_h,w ; don't increment timer_h
snc
setb timer_flag
movb led_pin,timer_h.6 ; once timer_h is changed, update the LED
:timer_out
clrb divider.divider_bit
inc divider ; do nothing unless divider_bit is a '1'
;*********************************************************************************
; Set Interrupt Rate
;*********************************************************************************
isr_end mov w,#-int_period ;refresh RTCC on return
retiw ;return from the interrupt
; = 1/(int_period*RTCC prescaler*1/50MHz)
; = 1/(217*1*20ns) = 4.34us
;*****************************************************************************************
; End of the Interrupt Service Routine
;*****************************************************************************************
;*****************************************************************************************
; RESET VECTOR
;*****************************************************************************************
;*********************************************************************************
; Program execution begins here on power-up or after a reset
;*********************************************************************************
reset_entry
;*********************************************************************************
; Initialise all port configuration
;*********************************************************************************
_mode ST_W ;point MODE to write ST register
mov w,#RB_ST ;Setup RB Schmitt Trigger, 0 = enabled, 1 = disabled
mov !rb,w
mov w,#RC_ST ;Setup RC Schmitt Trigger, 0 = enabled, 1 = disabled
mov !rc,w
IFDEF SX48_52
mov w,#RD_ST ;Setup RD Schmitt Trigger, 0 = enabled, 1 = disabled
mov !rd,w
mov w,#RE_ST ;Setup RE Schmitt Trigger, 0 = enabled, 1 = disabled
mov !re,w
ENDIF
_mode LVL_W ;point MODE to write LVL register
mov w,#RA_LVL ;Setup RA CMOS or TTL levels, 0 = TTL, 1 = CMOS
mov !ra,w
mov w,#RB_LVL ;Setup RB CMOS or TTL levels, 0 = TTL, 1 = CMOS
mov !rb,w
mov w,#RC_LVL ;Setup RC CMOS or TTL levels, 0 = TTL, 1 = CMOS
mov !rc,w
IFDEF SX48_52
mov w,#RD_LVL ;Setup RD CMOS or TTL levels, 0 = TTL, 1 = CMOS
mov !rd,w
mov w,#RE_LVL ;Setup RE CMOS or TTL levels, 0 = TTL, 1 = CMOS
mov !re,w
ENDIF
_mode PLP_W ;point MODE to write PLP register
mov w,#RA_PLP ;Setup RA Weak Pull-up, 0 = enabled, 1 = disabled
mov !ra,w
mov w,#RB_PLP ;Setup RB Weak Pull-up, 0 = enabled, 1 = disabled
mov !rb,w
mov w,#RC_PLP ;Setup RC Weak Pull-up, 0 = enabled, 1 = disabled
mov !rc,w
IFDEF SX48_52
mov w,#RD_PLP ;Setup RD Weak Pull-up, 0 = enabled, 1 = disabled
mov !rd,w
mov w,#RE_PLP ;Setup RE Weak Pull-up, 0 = enabled, 1 = disabled
mov !re,w
ENDIF
_mode DDIR_W ;point MODE to write DDIR register
mov w,#RA_DDIR ;Setup RA Direction register, 0 = output, 1 = input
mov !ra,w
mov w,#RB_DDIR ;Setup RB Direction register, 0 = output, 1 = input
mov !rb,w
mov w,#RC_DDIR ;Setup RC Direction register, 0 = output, 1 = input
mov !rc,w
IFDEF SX48_52
mov w,#RD_DDIR ;Setup RD Direction register, 0 = output, 1 = input
mov !rd,w
mov w,#RE_DDIR ;Setup RE Direction register, 0 = output, 1 = input
mov !re,w
ENDIF
mov w,#RA_latch ;Initialize RA data latch
mov ra,w
mov w,#RB_latch ;Initialize RB data latch
mov rb,w
mov w,#RC_latch ;Initialize RC data latch
mov rc,w
IFDEF SX48_52
mov w,#RD_latch ;Initialize RD data latch
mov rd,w
mov w,#RE_latch ;Initialize RE data latch
mov re,w
ENDIF
;*********************************************************************************
; Clear all Data RAM locations
;*********************************************************************************
IFDEF SX48_52 ;SX48/52 RAM clear routine
mov w,#$0a ;reset all ram starting at $0A
mov fsr,w
:zero_ram clr ind ;clear using indirect addressing
incsz fsr ;repeat until done
jmp :zero_ram
_bank bank0 ;clear bank 0 registers
clr $10
clr $11
clr $12
clr $13
clr $14
clr $15
clr $16
clr $17
clr $18
clr $19
clr $1a
clr $1b
clr $1c
clr $1d
clr $1e
clr $1f
ELSE ;SX18/20/28 RAM clear routine
clr fsr ;reset all ram banks
:zero_ram sb fsr.4 ;are we on low half of bank?
setb fsr.3 ;If so, don't touch regs 0-7
clr ind ;clear using indirect addressing
incsz fsr ;repeat until done
jmp :zero_ram
ENDIF
;*********************************************************************************
; Initialize program/VP registers
;*********************************************************************************
bank sin_gen_bank
; mov curr_sin,#32 ;init variables. A sine starts at 1, a cos wave starts at 0.
; mov sinvel,#0
mov curr_sin,#-4 ; use these values for a wave which is 90 degrees out of phase.
mov sinvel,#-8
mov curr_sin2,#-4 ; use these values for a wave which is 90 degrees out of phase.
mov sinvel2,#-8
call @disable_o
;*********************************************************************************
; Setup and enable RTCC interrupt, WREG register, RTCC/WDT prescaler
;*********************************************************************************
RTCC_ON = %10000000 ;Enables RTCC at address $01 (RTW hi)
;*WREG at address $01 (RTW lo) by default
RTCC_ID = %01000000 ;Disables RTCC edge interrupt (RTE_IE hi)
;*RTCC edge interrupt (RTE_IE lo) enabled by default
RTCC_INC_EXT = %00100000 ;Sets RTCC increment on RTCC pin transition (RTS hi)
;*RTCC increment on internal instruction (RTS lo) is default
RTCC_FE = %00010000 ;Sets RTCC to increment on falling edge (RTE_ES hi)
;*RTCC to increment on rising edge (RTE_ES lo) is default
RTCC_PS_ON = %00000000 ;Assigns prescaler to RTCC (PSA lo)
RTCC_PS_OFF = %00001000 ;Assigns prescaler to RTCC (PSA lo)
PS_000 = %00000000 ;RTCC = 1:2, WDT = 1:1
PS_001 = %00000001 ;RTCC = 1:4, WDT = 1:2
PS_010 = %00000010 ;RTCC = 1:8, WDT = 1:4
PS_011 = %00000011 ;RTCC = 1:16, WDT = 1:8
PS_100 = %00000100 ;RTCC = 1:32, WDT = 1:16
PS_101 = %00000101 ;RTCC = 1:64, WDT = 1:32
PS_110 = %00000110 ;RTCC = 1:128, WDT = 1:64
PS_111 = %00000111 ;RTCC = 1:256, WDT = 1:128
mov w,#RTCC_PS_OFF ;setup option register
mov !option,w
jmp @main
;*****************************************************************************************
; MAIN PROGRAM CODE
;*****************************************************************************************
;*********************************************************************************
; Main
;*********************************************************************************
main
jmp start_2
_FSK_IO jmp FSK_IO ; Jump table for FSK_IO
start_2
;**************************************************************************
; Main Code:
; -Sends Prompt
; -Waits for input from UART
; -Responds to these commands:
; D - Dial Mode
; F - FSK Input/Output mode.
; T - FSK Transmit only (Voltage --> Frequency conversion)
; R - FSK Receive only (Frequency --> Voltage conversion)
;**************************************************************************
mov w,#_hello ; send hello string
call @send_string
mov w,#_instructions ; send instructions
call @send_string
mov w,#_instructions2 ; send more instructions
call @send_string
:_cmd_loop clr flags
call @get_byte ; wait for an input character
call @uppercase ; convert it to uppercase
cje byte,#'T',TX_ONLY ; T enables transmit-only mode
cje byte,#'R',RX_ONLY ; R enables receive-only mode
cje byte,#'F',FSK_IO ; F enables FSK I/O (half-duplex) mode
cjne byte,#'D',:_cmd_loop ; if it is not = 'D', wait for it.
;**************************************************************************
; Dial Mode:
; -Dials contents of ascii buffer, starting from location pointed
; to by ascii_index.
; -Responds to these commands:
; 0-9, *, # - Dials the specified number
; , - Pause for 2 seconds
; -Jumps to data mode after dialing.
;**************************************************************************
DIAL_MODE
clrb ring_det_en
mov w,#_CR
call @send_string
mov w,#_DIALING ; send Dialing
call @send_string
setb hook ; pick up the line
:dial_loop call @buffer_get ; wait for an input character
call @uppercase ; convert it to uppercase
mov w,byte
snz
jmp FSK_IO
call @send_byte
cje byte,#',',:pause ; if the character = ',', pause for 2s
call @digit_2_index ; convert the ascii digit to an
; index value
call @load_frequencies ; load the frequency registers
call @dial_it ; dial the number for 60ms and return.
:inc call @inc_ascii_index ; increment the index into the table
jmp :dial_loop
:pause
mov w,#201 ; delay 2s
call @delay_10n_ms
jmp :inc
;**************************************************************************
; FSK Input/Output mode:
; -Sends Prompt
; -Sends any characters received from the terminal through the phone line
; and sends any characters received from the phone line to the terminal
; -performs retw 0 when it detects incoming '+++' from UART
;**************************************************************************
FSK_IO
mov w,#_CR
call @send_string
mov w,#_PROMPT
call @send_string
bank sin_gen_bank
mov curr_sin2,#-4 ; set up so the wave starts at close to the right spot (0).
mov sinvel2,#-8
clr flags
setb fsk_rx_en ; enable the FSK detector
bank serial
:RESET_PLUSES mov plus_count,#3 ; counts the number of '+'s received
:TX_LOOP
jb fsk_rx_flag,:fsk_byte_received ; if FSK received a byte, go to :fsk_byte_received
jb rx_flag,:byte_received ; if the UART received a byte, go to :byte_received
jmp :TX_LOOP
:byte_received
bank serial ; echo the character back to the terminal
mov byte,rx_byte
clrb rx_flag ; clear the flag
call @fsk_transmit_byte ; send the byte via. FSK
bank serial
mov w,byte
xor w,#'+'
jnz :RESET_PLUSES
dec plus_count
snz
retw 0
jmp :TX_LOOP ; return to the loop
:fsk_byte_received
bank fsk_receive_bank ; send the character to the terminal
mov w,fsk_rx_byte
clrb fsk_rx_flag ; clear the flag
call @send_byte
jmp :TX_LOOP ; return to the loop
;**************************************************************************
; FSK send only mode:
; -Sends Prompt
; -Outputs 1300Hz for a high on RX_pin and 2100Hz for a low on RX_pin
;**************************************************************************
TX_ONLY
mov w,#_TYPE ; send Type instruction
call @send_string
setb hook
bank sin_gen_bank
bank sin_gen_bank
mov curr_sin2,#-4 ; set up so the wave starts at close to the right spot (0).
mov sinvel2,#-8
mov curr_sin,#0 ; make the output of sin gen 1=0
enable_o
setb fsk_tx_en
:passthroughloop
jb rx_pin,:high_data
:low_data
bank sin_gen_bank
mov freq_count_high2,#f2100_h ; set up the sine generator to
mov freq_count_low2,#f2100_l ; output 2100 Hz.
jmp :passthroughloop
:high_data bank sin_gen_bank
mov freq_count_high2,#f1300_h
mov freq_count_low2,#f1300_l
jmp :passthroughloop
:new_byte bank serial
mov w,rx_byte
call @send_byte
clrb rx_flag
jmp :passthroughloop
;**************************************************************************
RX_ONLY
; FSK receive only mode:
; -Sends Prompt
; -Outputs a high on tx_pin for 1300Hz and a low on tx_pin for 2100Hz
;**************************************************************************
mov w,#_TYPE ; send Type instruction
call @send_string
setb hook
call @disable_o
setb fsk_rx_en
:passthroughloop
bank fsk_receive_bank
jb fsk_current_in,:high_data
:low_data
clrb tx_pin
jmp :passthroughloop
:high_data
setb tx_pin
jmp :passthroughloop
;**************************************************************************
HANG_UP ; goes on-hook
mov w,#_CR
call @send_string
mov w,#_OK
call @send_string
clrb hook
retw 0
;**************************************************************************
INITIALIZE ; calls init routine
mov w,#_CR
call @send_string
mov w,#_OK
call @send_string
jmp @reset_entry
org $200
;**************************************************************************
; Miscellaneous subroutines
;**************************************************************************
;**************************************************************************
buffer_push
; This subroutine pushes the contents of byte onto the 32-byte ascii buffer.
;**************************************************************************
bank serial ; Move the byte into the buffer
mov temp,byte
mov fsr,#ascii_buffer
add fsr,ascii_index
mov indf,temp
; Increment index and keep it in range
call @inc_ascii_index
mov fsr,#ascii_buffer ; Null terminate the buffer.
add fsr,ascii_index
clr indf
bank serial
retp
;**************************************************************************
;**************************************************************************
buffer_backspace
; This subroutine deletes one value of the buffer and decrements the index
;**************************************************************************
dec ascii_index
and ascii_index,#%01101111
mov fsr,#ascii_buffer
add fsr,ascii_index
clr indf
bank serial
retp
;**************************************************************************
inc_ascii_index
; This subroutine increments the index into the buffer
;**************************************************************************
mov w,ascii_index
and w,#%00001111
xor w,#%00001111
jnz :not_on_verge
inc ascii_index
mov w,#16
add w,ascii_index
and w,#$7f
mov ascii_index,w
retp
:not_on_verge
inc ascii_index
retp
;**************************************************************************
buffer_get
; This subroutine retrieves the buffered value at index
;**************************************************************************
mov fsr,#ascii_buffer
add fsr,ascii_index
mov w,indf
bank serial
mov byte,w
retp
;**************************************************************************
;**************************************************************************
delay_10n_ms
; This subroutine delays 'w'*10 milliseconds.
; This subroutine uses the TEMP register
; INPUT w - # of milliseconds to delay for.
; OUTPUT Returns after 10 * n milliseconds.
;**************************************************************************
mov temp,w
bank timers
:loop clrb timer_flag ; This loop delays for 10ms
mov timer_h,#$0f4
mov timer_l,#$004
jnb timer_flag,$
dec temp ; do it w-1 times.
jnz :loop
clrb timer_flag
retp
;**************************************************************************
delay_n_ms
; This subroutine delays 'w' milliseconds.
; This subroutine uses the TEMP register
; INPUT w - # of milliseconds to delay for.
; OUTPUT Returns after n milliseconds.
;**************************************************************************
mov temp,w
bank timers
:loop clrb timer_flag ; This loop delays for 1ms
mov timer_h,#$0fe
mov timer_l,#$0cd
jnb timer_flag,$
dec temp ; do it w-1 times.
jnz :loop
clrb timer_flag
retp
;**************************************************************************
zero_ram
; Subroutine - Zero all ram.
; INPUTS: None
; OUTPUTS: All ram locations (except special function registers) are = 0
;**************************************************************************
CLR FSR
:loop SB FSR.4 ;are we on low half of bank?
SETB FSR.3 ;If so, don't touch regs 0-7
CLR IND ;clear using indirect addressing
IJNZ FSR,:loop ;repeat until done
retp
;**************************************************************************
; Subroutine - Get byte via serial port and echo it back to the serial port
; INPUTS:
; -NONE
; OUTPUTS:
; -received byte in rx_byte
;**************************************************************************
get_byte jnb rx_flag,$ ;wait till byte is received
clrb rx_flag ;reset the receive flag
bank serial
mov byte,rx_byte ;store byte (copy using W)
; & fall through to echo char back
retp
;**************************************************************************
; Subroutine - Get byte via Bell202 FSK and send it to the serial port
; INPUTS:
; -NONE
; OUTPUTS:
; -received byte in fsk_rx_byte
;**************************************************************************
fsk_get_byte jnb fsk_rx_flag,$ ;wait till byte is received
clrb fsk_rx_flag ;reset the receive flag
bank fsk_receive_bank
mov byte,fsk_rx_byte ;store byte (copy using W)
; & fall through to echo char back
;**************************************************************************
; Subroutine - Send byte via serial port
; INPUTS:
; w - The byte to be sent via RS-232
;**************************************************************************
send_byte bank serial
:wait test tx_count ;wait for not busy
jnz :wait ;
not w ;ready bits (inverse logic)
mov tx_high,w ; store data byte
setb tx_low.7 ; set up start bit
mov tx_count,#10 ;1 start + 8 data + 1 stop bit
RETP ;leave and fix page bits
;**************************************************************************
; Subroutine - Send string pointed to by address in W register
; INPUTS:
; w - The address of a null-terminated string in program
; memory
; OUTPUTS:
; outputs the string via. RS-232
;**************************************************************************
send_string bank serial
mov string,w ;store string address
:loop mov w,string ;read next string character
mov m,#4 ; with indirect addressing
iread ; using the mode register
mov m,#$F ;reset the mode register
test w ;are we at the last char?
snz ;if not=0, skip ahead
RETP ;yes, leave & fix page bits
call send_byte ;not 0, so send character
inc string ;point to next character
jmp :loop ;loop until done
;**************************************************************************
; Subroutine - Make byte uppercase
; INPUTS:
; byte - The byte to be converted
;**************************************************************************
uppercase csae byte,#'a' ;if byte is lowercase, then skip ahead
RETP
sub byte,#'a'-'A' ;change byte to uppercase
RETP ;leave and fix page bits
;**************************************************************************
; Subroutine - Disable the output (Enable the input)
;**************************************************************************
disable_o
ifdef old_board
setb in_out ; set the analogue switch for
else
clrb in_out
endif
bank PWM_bank ; input mode.
mov pwm0,#128 ; put 2.5V DC on PWM output pin
retp
;**************************************************************************
org $400
;**************************************************************************
; Jump table for page 2
;**************************************************************************
FSK_RECEIVE jmp _FSK_RECEIVE
;**************************************************************************
; String data (for RS-232 output) and tables
;**************************************************************************
_hello dw 13,10,13,10,'SX Modem V 3.53',13,10,13,10,0
_instructions dw '-D = Dial',13,10,'-F = FSK I/O Mode.',13,10,0
_instructions2 dw '-T = FSK TX only (Carrier)',13,10,'-R = FSK RX only',13,10,0
_FSK dw 13,10,'FSK I/O Mode.',0
_DIALING dw 13,10,'Dial Mode.',0
_RING dw 'RING',13,10,0
_PROMPT dw 13,10,'>',0
_CR dw 13,10,0
_TYPE dw 13,10,'Begin Typing...',13,10,0
_OK dw 13,10,'OK',13,10,0
;**************************************************************************
; FSK transmit/receive functions
;**************************************************************************
ring_detect jmp _ring_detect
;**************************************************************************
FSK_TX_UART ;(part of interrupt service routine)
; This subroutine creates an internal transmit UART using the data in
; fsk_tx_byte
;**************************************************************************
sb fsk_transmitting
RETP
sb divider.divider_bit ; divide the baud by divider_bit
RETP
bank fsk_transmit_bank
clrb fsk_bit_delay.7 ; multiply the baud by 2
dec fsk_bit_delay ; Decrement the delay counter
sz
RETP
stc ; set the carry bit to create a stop bit
rr fsk_tx_byte
sc
clrb fsk_last_bit
snc
setb fsk_last_bit
jb fsk_last_bit,:new_bit_is_high
:new_bit_is_low
bank sin_gen_bank
mov freq_count_high2,#f2100_h ; output a frequency of 2100Hz
mov freq_count_low2,#f2100_l
jmp :end_new_bit
:new_bit_is_high
bank sin_gen_bank
mov freq_count_high2,#f1300_h ; output a frequency of 1300Hz
mov freq_count_low2,#f1300_l
:end_new_bit
bank fsk_transmit_bank
decsz fsk_tx_counter
RETP
:FSK_DONE_TRANSMITTING
setb fsk_last_bit ; since we're done transmitting,
clrb fsk_transmitting ; clear the transmitting flag
RETP
;**************************************************************************
fsk_transmit_byte
; This subroutine initializes the FSK UART and the sine generator and then
; it transmits data via FSK modulation to an outside source. The byte to
; send is passed in the 'w' register. Returns when byte transmission is
; done and FSK wave is close to zero OR when another character is received
; via. RS-232. If another character is received via. RS-232, it immediately
; exits so that next character can begin transmission without re-initializing.
;**************************************************************************
jb fsk_transmitting,$ ; wait until done transmitting.
bank fsk_transmit_bank
mov fsk_tx_byte,w
:enable enable_o ; enable the outputs
bank fsk_transmit_bank
clr fsk_bit_delay ; since fsk_bit_delay goes from 0 (256) to zero,
; clear fsk_bit_delay to set up for the first bit.
clrb fsk_last_bit ; set fsk_last_bit to be an internal low (start bit)
mov fsk_tx_counter,#10 ; set up the bit counter for 1 start, 8 data, and 1 stop
bank sin_gen_bank
mov freq_count_high2,#f2100_h ; set up the sine generator to
mov freq_count_low2,#f2100_l ; output 2100 Hz.
mov curr_sin,#0 ; make the output of sin gen 1=0
; so it doesn't interfere with sin gen 2
bank fsk_transmit_bank ; enable the 2nd sin generator and the TX UART.
setb fsk_transmitting
setb fsk_tx_en
bank sin_gen_bank
:wait_loop snb rx_flag ; if another character is received, don't disable
retp ; output
jb fsk_transmitting,:wait_loop ; otherwise, wait until we are done transmitting
cjne curr_sin2,#-4,:wait_loop ; and wait until FSK signal is relatively close to zero.
clrb fsk_tx_en ; disable the FSK transmitter
setb fsk_rx_en ; enable the FSK receiver
call @disable_o ; disable the output
retp
;*************************************************************
;
_FSK_RECEIVE ; FSK receiver starts here.
;
;*************************************************************
bank fsk_receive_bank
add fsk_trans_count,#1 ; Regardless of what is going on, increment the
snc ; transition timer. These get cleared when a transition
jmp :roll_over_error ; takes place.
cjb fsk_trans_count,#low_high_th,:fsk_timer_out ; as soon as it takes longer than 95 counts
setb fsk_current_in ; to transition, this must be a low frequency
:fsk_timer_out
mov w,rb
and w,#%00000010 ; get the current state of rb.
xor w,rb_past_state ; compare it with the previous state of the pin
jz fsk_rx_out ; if there was no change, then jump out, there is nothing to do.
; Now it is time to determine if the transition that took place indicates a bit was received
; (it must be within some thresholds... below 20, ignore it, below 40, what???,
; below 95, high frequency, below 140, low frequency (already set), above 140,
; what???)
cjb fsk_trans_count,#glitch_th,:glitch_so_ignore ; pulse was below specs, ignore it... probably noise
cjb fsk_trans_count,#low_count_error_th,:error ; pulse was not a glitch but wasn't long enough to mean anything... huh?
cjb fsk_trans_count,#low_high_th,:high_frequency ; pulse was within specs for a high frequency...
cjb fsk_trans_count,#high_count_error_th,:fsk_receive_done ; pulse was within specs for a low frequency (don't do anything)
jmp :error ; pulse was too long to mean anything, so do nothing.
:high_frequency ; a high frequency corresponds to low data.
clrb fsk_current_in
jmp :fsk_receive_done
:roll_over_error ; if the counter rolls over, keep it in range.
;--------------- PUT ERROR HANDLING CODE IN HERE -----------------
mov fsk_trans_count,#high_count_error_th
clr fsk_rx_count
jmp :glitch_so_ignore
:error ; if there is another type of error, just clear
; any UART receive.
;--------------- PUT ERROR HANDLING CODE IN HERE -----------------
clr fsk_rx_count
:fsk_receive_done
clr fsk_trans_count ; clear the bit counter.
:glitch_so_ignore ; don't clear the counter if the data was a glitch
mov w,rb ; save the new state of RB.
and w,#%00000010
mov rb_past_state,w
fsk_rx_out
;**************************************************************************
:fsk_uart
; This is an asynchronous receiver. Written by Craig Webb. Modified by
; Chris Fogelklou for use with FSK receive routine.
;**************************************************************************
bank fsk_receive_bank
jnb divider.divider_bit,fsk_rx_done ; (Divide operation frequency by divider_bit)
movb c,fsk_current_in ; get current rx bit
test fsk_rx_count ; currently receiving byte?
jnz :rxbit ; if so, jump ahead
mov w,#9 ; in case start, ready 9 bits
sc ; skip ahead if not start bit
mov fsk_rx_count,w ; it is, so renew bit count
mov fsk_rx_divide,#start_delay ; ready 1.5 bit periods
:rxbit djnz fsk_rx_divide,fsk_rx_done ; middle of next bit?
setb fsk_rx_divide.baud_bit ; yes, ready 1 bit period
dec fsk_rx_count ; last bit?
sz ; if not
rr fsk_rx_byte ; then save bit
snz ; if so
setb fsk_rx_flag ; then set flag
fsk_rx_done
RETP
;**************************************************************************
; END FSK ROUTINES
;**************************************************************************
;**************************************************************************
; DTMF generate lookup tables. Gives the tone required for each of the
; DTMF digits.
;**************************************************************************
_0_ dw f941_h,f941_l,f1336_h,f1336_l
_1_ dw f697_h,f697_l,f1209_h,f1209_l
_2_ dw f697_h,f697_l,f1336_h,f1336_l
_3_ dw f697_h,f697_l,f1477_h,f1477_l
_4_ dw f770_h,f770_l,f1209_h,f1209_l
_5_ dw f770_h,f770_l,f1336_h,f1336_l
_6_ dw f770_h,f770_l,f1477_h,f1477_l
_7_ dw f852_h,f852_l,f1209_h,f1209_l
_8_ dw f852_h,f852_l,f1336_h,f1336_l
_9_ dw f852_h,f852_l,f1477_h,f1477_l
_star_ dw f941_h,f941_l,f1209_h,f1209_l
_pound_ dw f941_h,f941_l,f1477_h,f1477_l
;**************************************************************************
_ring_detect
; Ring detect has 3 functions:
; - It filters out the 20Hz pulsing of the ring-line by using
; a software monostable with an 80ms timeout. If the length
; of time between pulses exceeds 80ms, the "ringing_1" flag gets
; cleared. This can also be used to show the pause between
; rings in a distinctive ring pattern.
; - It uses another monostable with a timeout of 530ms to
; filter out distinctive ring pauses, whose largest pause
; between distinctive rings is 525ms. If the pause exceeds
; the 530ms timeout, the "ring_occured" flag is set, indicating
; that a ring is complete.
; - A duration timer is used to find the amount of time the
; line was ringing between pauses. This can be used to
; decode distinctive ring. The register is called
; ring_duration. The duration is saved as soon as a pause is
; found.
;**************************************************************************
bank ring_detect_bank
;******************************************************************
; First run a timer that rolls over every 10ms, so all other timers
; can sync to it.
;******************************************************************
inc ring_timer_low
jnz :no_roll_1
inc ring_timer_high
jnz :no_roll_1
setb ring_timer_flag
mov ring_timer_low,#$04
mov ring_timer_high,#$f4
:no_roll_1
;******************************************************************
; Now create a monostable that times out after 80ms, because this
; is the maximum amount of time between two pulses of the ring
; signal. Ringing gets cleared when this monostable times out.
;******************************************************************
jb ring,:check_for_duration
:ring_low
mov ring_off_timer_1,#9 ; if the ring line is low, set up
setb ringing_1
jb ringing_2,:check_for_duration
mov ring_timer,#221
setb ringing_2
:check_for_duration
jnb ring_timer_flag,:ring_detect_done ; jump out if the timer_flag is not set.
clrb ring_timer_flag
jnb ringing_1,:not_ringing_1
inc ring_duration_timer ; count the ring duration
snz
setb long_ring
dec ring_off_timer_1 ; while it is ringing.
jnz :not_ringing_1
:done_short_ring
clrb ringing_1 ; clear the flag that indicates
; it is ringing.
mov ring_duration,ring_duration_timer ; and save the duration
; of the ring.
clr ring_duration_timer ; reset the timer which times how
; long each ring is.
setb ring_pause ; indicate pause between rings.
:not_ringing_1 ; Now check if the 530ms monostable
; has timed out.
jnb ringing_2,:ring_detect_done
dec ring_timer
jnz :ring_detect_done
:done_whole_ring
clrb ringing_2
setb ring_captured
:ring_detect_done
retp
;**************************************************************************
; Done ring detection interrupt service routine
;**************************************************************************
org $600
;**************************************************************************
; DTMF transmit functions/subroutines
;**************************************************************************
;**************************************************************************
digit_2_index
; This subroutine converts a digit from 0-9 or a '*' or a '#' to a table
; lookup index which can be used by the load_frequencies subroutine. To use
; this routine, pass it a value in the 'byte' register. No invalid digits
; are used. (A, B, C, or D)
;**************************************************************************
bank serial
cja byte,#'9',:error ; if the character is above 9, then error (get another char)
cje byte,#'*',:star
cje byte,#'#',:pound
cjb byte,#'0',:error
sub byte,#'0' ; convert to decimal number
jmp :got_it
:star mov byte,#10
jmp :got_it
:pound mov byte,#11
:got_it retp
:error
mov byte,#$0FF
retp
;**************************************************************************
load_frequencies
; This subroutine loads the frequencies using a table lookup approach.
; The index into the table is passed in the byte register.
;**************************************************************************
bank serial
cje byte,#$0FF,:end_load_it
clc
rl byte
rl byte ; multiply byte by 4 to get offset
add byte,#_0_ ; add in the offset of the first digit
mov temp,#4
mov fsr,#freq_count_high
bank serial
:dtmf_load_loop mov m,#5
mov w,byte
IREAD ; get the value from the table
bank sin_gen_bank ; and load it into the frequency
mov indf,w ; register
bank serial
inc byte
inc fsr
decsz temp
jmp :dtmf_load_loop ; when all 4 values have been loaded,
:end_load_it retp ; return
;**************************************************************************
dial_it ; This subroutine puts out whatever frequencies were loaded
; for 60ms, and then stops outputting the frequencies.
;**************************************************************************
bank serial
cje byte,#$0FF,:end_dial_it
bank sin_gen_bank
mov curr_sin,#-4 ; use these values to start the wave at close to zero crossing.
mov sinvel,#-8
mov curr_sin2,#-4 ; use these values to start the wave at close to zero crossing.
mov sinvel2,#-8
enable_o ; enable the output
mov w,#6
call @delay_10n_ms ; delay 20ms
setb dtmf_gen_en ; dial the number
mov w,#11
call @delay_10n_ms ; delay 100ms
clrb dtmf_gen_en ; stop dialing
call @disable_o ; now disable the outputs
:end_dial_it retp
;**************************************************************************
sine_generator1 ;(Part of interrupt service routine)
; This routine generates a synthetic sine wave with values ranging
; from -32 to 32. Frequency is specified by the counter. To set the
; frequency, put this value into the 16-bit freq_count register:
; freq_count = FREQUENCY * 6.83671552 (@50MHz)
;**************************************************************************
bank sin_gen_bank
add freq_acc_low,freq_count_low;2 ; advance sine at frequency
jnc :no_carry ;2,4 ; if lower byte rolls over
inc freq_acc_high ; carry over to upper byte
jnz :no_carry ; if carry causes roll-over
mov freq_acc_high,freq_count_high ; then add freq counter to accumulator (which should be zero,
; so move will work)
; and update sine wave
jmp :change_sin
:no_carry
add freq_acc_high,freq_count_high ; add the upper bytes of the accumulators
jnc :no_change
:change_sin
mov w,++sinvel ;1 ; if the sine wave
sb curr_sin.7 ;1 ; is positive, decelerate
mov w,--sinvel ;1 ; it. Otherwise, accelerate it.
mov sinvel,w ;1
add curr_sin,w ;1 ; add the velocity to sin
:no_change
;**************************************************************************
sine_generator2 ;(Part of interrupt service routine)
; This routine generates a synthetic sine wave with values ranging
; from -32 to 32. Frequency is specified by the counter. To set the
; frequency, put this value into the 16-bit freq_count register:
; freq_count = FREQUENCY * 6.83671552 (@50MHz)
;**************************************************************************
bank sin_gen_bank
add freq_acc_low2,freq_count_low2;2 ;advance sine at frequency
jnc :no_carry ;2,4 ; if lower byte rolls over
inc freq_acc_high2 ; carry over to upper byte
jnz :no_carry ; if carry causes roll-over
mov freq_acc_high2,freq_count_high2 ; then add freq counter to accumulator (which should be zero,
; so move will work)
; and update sine wave
jmp :change_sin
:no_carry
add freq_acc_high2,freq_count_high2 ; add the upper bytes of the accumulators
jnc :no_change
:change_sin
mov w,++sinvel2 ;1 ; if the sine wave
sb curr_sin2.7 ;1 ; is positive, decelerate it
mov w,--sinvel2 ;1 ; it. Otherwise, accelerate it.
mov sinvel2,w ;1
add curr_sin2,w ;1 ; add the velocity to sin
:no_change
jb dtmf_gen_en,:do_DTMF
mov pwm0,curr_sin ; mov the value of SIN into the PWM output
add pwm0,curr_sin2 ; mov the value of SIN2 into the PWM output
clc
rl pwm0 ; double the value of the PWM output
add pwm0,#128 ; put it in the middle of the output range
retp ; return with page bits intact
:do_DTMF ; If we are doing DTMF generation, then we need to add "twist" to the
; signal (divide sin2 by 4 and add it to it's original value)
mov pwm0,curr_sin2 ; mov sin2 into pwm0
mov IRQ_temp,w ; mov the high_frequency sin wave's current value
clc ; into a temporary register
snb IRQ_temp.7 ; divide temporary register by four by shifting right
stc ; (for result = (0.25)(sin2))
rr IRQ_temp
clc
snb IRQ_temp.7
stc
mov w,>>IRQ_temp
add pwm0,w ; (1.25)(sin2) = sin2 + (0.25)(sin2)
add pwm0,curr_sin ; add the value of SIN into the PWM output
; for result = pwm0 = 1.25*sin2 + 1*sin
add pwm0,#128 ; put pwm0 in the middle of the output range (get rid of negative values)
retp ; return with page bits intact
| file: /Techref/scenix/lib/io/dev/modem/bell202_modem.src, 68KB, , updated: 2001/10/27 13:23, local time: 2024/10/31 17:08,
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